JPH10279554A - New ionic conductive substance provided with improved conductivity and stability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound useful as an operatic solvent, etc., used for producing lithium batteries, ion-conducting materials, etc. SOLUTION: A sulfamide of the formula: R1 R2 NSO2 NR3 R4 (one to three R groups are each methyl, and the others are each ethyl, or one of the R groups is methoxyethyl, and the others are each methyl or ethyl). The compound is added together with an auxiliary solvent such as ethylene glycol to a dissociating salt, e.g. a lithium salt such as LiBF4 , to provide an electrolytic composition having excellent conductivity. The compound is also mixed with an aprotic polymer such as a polyether containing ethylene oxide units to give an electrolytic composition. The electrolytic composition is useful for lithium batteries, electrochemical devices, etc., and can be used as stable ion-conductive materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to ionic conductive materials having improved conductivity and stability. More specifically,
The present invention provides a compound represented by the formula: R ₁ R ₂ NSO ₂ NR ₃ R _{4 wherein} R ₁ ,
R ₂ , R ₃ and R ₄ are methyl groups and the remaining groups are ethyl groups, or _one of R ₁ , R ₂ , R ₃ and R ₄ is a methoxyethyl group and the remaining groups are A methyl or ethyl group), which is an ionic conductive material when a salt is added as an aprotic solvent usable as a medium for organic reaction and / or synthesis or as a solute to the sulfamide of the above formula. When a sulfamide and a salt of the above formula are added to a solid or liquid polymer, the sulfamide and the salt are used as a solid or gel polymer electrolyte useful for electrochemical applications such as lithium type batteries, so-called rocking chairs or lithium ion batteries.

[0002]

[Prior art]

Sulfamides of the formula: R ₁ R ₂ NSO ₂ NR ₃ R ₄ , wherein R ₁ , R ₂ , R ₃ and R ₄ represent alkyl groups, and derivatives thereof, are used in a number of chemical and biological applications Have been. R
ikey et al. (Journal of Organic
Chemistry, Vol. 52, no. 4 (19
87) pp. 479-483) report that such compounds are particularly stable to polar organometallic compounds and other strongly basic and nucleophilic reagents when used as solvents. According to Richey et al., Organomagnesium compounds are infinitely stable in tetraethylsulfamide (referred to as TES) where R ₁ , R ₂ , R ₃ and R ₄ are all ethyl groups, and butyllithium in TES The half-life was found to be over 15 minutes, but the half-life in other solvents was less than 5 minutes.

[0003] Sulfamide is used in the agricultural chemical field (US Pat.
596,017) and biological applications. U.S. Pat. No. 5,506,355 describes a method for producing a sulfamide compound. US Patent No. 3,8
Nos. 79,528, 5,539,102 and 3,92
No. 3,886 describes a route and method for producing sulfamide compounds for these uses.

It is also well known that sulfamides can increase the flame resistance of polymers. U.S. Pat. No. 3,888,819
No. 3,915,931 describe this special purpose sulfamide composition and its preparation.

[0005] Proton vacancy conducting polymers based on polyethylene oxide (PEO) and sulfamide type salts are also new basic proton conducting polymers as Bermude.
Z et al. (Electrochimica Act)
a, Vol. 37, no. 9, (1992) 1603-
1609). The presence of sulfamide-type salts is the main focus of this proton conducting polymer concept.

In the field of lithium batteries, the performance of PEO polymers modified with sulfonamide end groups is known as PEO
Provides better conductivity than the system alone. For example, PEO
_It has been shown that PEO having an alkylsulfonamide terminal group such as 1000- (NKSO ₂ Me) ₂ has higher ionic conductivity than PEO ₁₀₀₀ (Solid State Ion).
ics, 86-88, (1996), 325-328.
P.). The authors explain that the high conductivity is due to the high dissociation constant of the terminal sulfonamide.

[0007] Finding new solvents with high dielectric constants and solvation capacities (sufficiently high donor numbers (DN) and acceptor numbers (AN)) and low viscosities has been a key to the development of high energy lithium batteries operating at ambient temperature. is important. Also useful are solvent mixtures aimed at improving overall battery performance, as exemplified, for example, in US Pat. No. 4,129,691. These solvents can be used in liquid lithium batteries and gel electrolytes containing polymer networks (U.S. Pat. Nos. 4,792,504 and 5,501,1).
No. 920).

[0008] US Patent Nos. 4,851,307 and 5,
No. 063,124 has a general formula: R ₁ R ₂ NS0 ₂ NR ₃ R ₄
(Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently C (1-
10) The salt is dissolved in a solvent which is an alkyl group or a sulfamide derivative of C (1-10) oxaalkyl group) or a salt and a polymer having a solvation group are mixed in a variable amount of this solvent. Novel ionic conductive materials are described. A representative example of this group is R ₁ = R ₂ = R ₃ = R ₄ = ethyl (T
This compound is considered as a reference molecule in the following description.

However, US Pat. Nos. 4,851,307 or 5,063,124 do not report or claim particular chemical or electrochemical properties or advantages of selecting particular R groups. The relative position of these groups on a single nitrogen atom is not described.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide various R _i groups and various chemical properties to be useful in various applications such as lithium batteries and other general fields of organic chemistry. And to provide a new sulfamide system.

Another object of the present invention is to provide a sulfamide system that can be used as an aprotic solvent for organic reactions and / or synthesis.

It is another object of the present invention to provide a derivative of the present invention for providing a sulfamide derivative that can be used in the manufacture of ionic conductive materials, solid or gel polymer electrolytes or solid and liquid electrolytes.

Another object of the present invention is to provide sulfamide compositions having chemical and electrochemical properties that are particularly advantageous for use as solvents for chemical and electrochemical reactions.

It is another object of the present invention to provide sulfamides having particularly advantageous properties for use in solvents for chemical and electrochemical reactions, especially liquid and / or solid and / or gel lithium batteries or rocking chair batteries. It is.

[0015]

Means for Solving the Problems The present invention provides a compound represented by the general formula: R ₁ R ₂ NSO ₂ NR ₃ R _{4 wherein}
The three R substituents are methyl groups and the remainder is an ethyl group, or one R is a methoxyethyl group and the remaining R is a methyl or ethyl group). It relates to sulfamides or mixtures for protic solvents.

When R ₁ = R ₂ = R ₃ = methyl and R ₄ = ethyl, sulfamide has a dielectric constant of 57 and -33
It has a melting point of ° C.

When R ₁ = R ₂ = methyl and R ₃ = R ₄ = ethyl, the sulfamide has a dielectric constant of 40.5 and-
It has a melting point of 24 ° C and a glass transition temperature of -122 ° C.

When R ₁ = R ₃ = methyl and R ₂ = R ₄ = ethyl, the sulfamide has a dielectric constant of 44 and -56.
C. and a glass transition temperature of -130.degree.

When R ₁ = R ₂ = R ₃ = methyl and R ₄ = methoxyethyl, the sulfamide has a dielectric constant of 41.7 and a glass transition temperature of -110 ° C.

When R ₁ = R ₂ = R ₃ = ethyl and R ₄ = methoxyethyl, the sulfamide has a dielectric constant of 29, a glass transition temperature of -118 ° C. and a 0-5 V vs. Lithium stability window
With.

The present invention also relates to an electrolyte composition comprising at least one of the above sulfamide compositions and at least one dissociable salt dissolved in the composition. The sulfamide may be a mixture with a co-solvent and the salt may be a lithium salt.

According to a preferred embodiment, the lithium salt is LiBF
₄ , LiPF ₆ , Li (R _F SO ₂ ) ₂ N, Li (R _F S
O ₂ ) ₃ C, wherein R _F is fluorine or a fluorocarbon group having 1 to 4 carbon atoms.

The auxiliary solvent can be selected from the group consisting of dimethyl ethers of ethylene glycol, diethylene glycol and triethylene glycol and / or ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone.

In the electrolyte composition, the sulfamide may be aprotic, such as polyethers containing at least 70% ethylene oxide units, poly (methyl methacrylate), poly (acrylonitrile), and copolymers containing at least 70% vinylidene fluoride units. It may be a mixture with a polymer.

The ratio of sulfamide to polymer is preferably less than 20%, and the sulfamide acts as a plasticizer.

The ratio of solvent to polymer is greater than 50%,
The resulting mixture constitutes a gel.

[0027] The present invention further relates to a lithium battery wherein the electrolyte comprises the above electrolyte composition as a sole component or as a component of a composite electrode. In this battery, the negative electrode can be one containing lithium metal, a lithium alloy, a carbon insertion compound or a low voltage insertion oxide or nitride, and the positive electrode can be vanadium oxide, manganese oxide, cobalt oxide, nickel oxide, iron phosphate, pyrophosphate Those containing a high voltage insertion electrode derived from iron, iron manganese phosphate or iron manganese pyrophosphate can be used. The positive electrode may include polydisulfide or sulfur mixed with a conductive additive such as high surface area carbon.

[0028] The present invention further relates to a supercapacitive device wherein the electrolyte comprises the above composition and the electrode may comprise high surface area carbon.

The present invention further relates to an electrochemical device wherein the electrolyte comprises the composition described above and one of the electrodes can be a thin film of tungsten trioxide.

The present invention further relates to a solvent composition for a medium containing the above sulfamide alone or as a mixture with an organic solvent. Such compositions may contain co-solvents such as aromatic hydrocarbons, halocarbons, etc. for organic reactions such as carbanion production, Friedel-Crafts reaction, Diels-Alder or Michaelis reaction, cationic or anionic polymerization. Can be used as a medium.

[0031]

DETAILED DESCRIPTION OF THE INVENTION The following points are known to those skilled in the art.

Short alkyl groups usually result in molecules having a low degree of conformational freedom, which results in an increase in the melting point, viscosity or glass transition temperature T _{g of the} glass-forming composition. For example, to give a well-known example, propylene carbonate transforms to glass below −40 ° C., and ethylene carbonate has a melting point T _mp
= 39 ° C., T _mp = 4 ° C. for dimethyl carbonate, T _mp = −43 ° C. for diethyl carbonate, T _{mp for} acetonitrile
_mp = -48 ° C, propionitrile _Tmp = -93 ° C. The melting point of tetramethylsulfamide (abbreviated as TMS) is 73 ° C.

Short alkyl groups, in particular methyl, have low electron emission properties and the Gutmann definition of the corresponding molecule built from these alkyl chains [V. Gutmann, E
electrochimica Acta 21,661
-670, (1976)] is low (ie acetonitrile DN = 14.1, butyronitrile DN = 16.6). On the other hand, the number of acceptors (AN) is usually not significantly affected by the chain length (ethanol AN =
37, n-butanol AN = 36.8).

The oxidation stability of the ether group is 3.8 V v
s. Do not cross the lithium reference electrode.

An increase in the dielectric constant usually leads to an increase in the reactivity, since the dipoles are highly charged and / or close to the outer part of the molecule and are easily exposed to the reactants.

When the ethyl group is successively replaced with a methyl group, TES
The properties can be expected to change progressively as one moves from to TMS. Surprisingly, excellent behavior was observed with these compounds and compounds containing an ether linkage at the methoxyethyl substituent. Such a property was not expected or expected by those skilled in the art, and thus clearly supports the novelty of the present invention.

The key properties useful as solvents for chemical and electrochemical applications include the liquid temperature range, alone or as a mixture with polar polymers, the dielectric constant (e), the number of donors (DN), the number of acceptors ( AN) and the glass transition temperature (T _g ). In electrochemical applications, the specific conductivity can be increased by the characteristic values of the former three parameters. In battery applications, the window of electrochemical stability to the threshold potential at which lithium metal and solvent oxidation occur is also a very important property and needs to be as wide as possible.

A good solvent for liquid lithium batteries is low viscosity,
It must have a high boiling point, a low melting point and be able to dissolve large amounts of salts (high DN and AN). In lithium solid polymer batteries, a solvent can be used as a plasticizer (typically less than 50% by volume of a small amount of solvent is added to the polymer). In this particular application, the T _{g of} the polymer matrix
And those that reduce their crystallinity are good plasticizers.
In a gel electrolyte (a large amount of solvent of 50% or more immobilized on a compatible polymer matrix), the above properties are important because the ion transport mechanism (specific conductivity) can depend on both media (solvent and polymer). is there.

The invention will now be further described by way of non-limiting examples.

[0040] EXAMPLES Example 1 below (Me = methyl, Et = ethyl, s is conductivity (mS
/ Cm), e is the dielectric constant, DN and AN are the number of donors and acceptors according to Gutmann's definition, respectively, and n. m. Is not measurable, n. misc is immiscible) summarizes some of the properties of the novel sulfamides and demonstrates the excellent behavior of these compounds.

[0041]

[Table 1]

Example 2 In this example, the conductivity of a solution containing 0.33 mol / kg of LiTFSI in a solvent NES-I-4 (highest dielectric constant) was determined by changing the conductivity of TES-LiTFSI (TESA) having the same salt concentration.
Compare with the conductivity of the system. Beckman model RC-1
5 Conductivity data is measured at various temperatures (−20 ° C. to 55 ° C.) using an in-house built bridge similar to a commercial bridge.
The resistance is measured at 1 and 3 kHz using a platinum-plated platinum Orion (Boston, USA) cell and extrapolated to 0 kHz.

As apparent from FIG. 1, when three ethyl groups of TES are substituted with three methyl groups, (NES-I-
4) The conductivity increases more than three times at all temperatures.

Example 3 This example demonstrates the conductivity of a PEO-LiTFSI mixture. A sample is prepared as follows. 1) PEO (M
w = 4 × 10 ⁶ ) and LiTFSI are dissolved in acetonitrile. 2) After applying the resulting solution to an inert support, dry at ambient temperature under partial vacuum (40 mmHg) for 2-3 hours. 3) The electrolyte film is dried under reduced pressure at 140 ° C. for 48 hours. NES-I-6 as plasticizer or diluent
Alternatively, a sample to which TES is added is similarly prepared. NES-I- was added to a mixture of PEO-LiTFSI in acetonitrile.
6 or TES is added and the same procedure is followed except that the final drying step is performed at 2 mm Hg at ambient temperature for 48 hours.
NES-I-6 or TES in final solid electrolyte film
The concentration is confirmed by ¹ H NMR.

Next, an SPE film is placed between the two stainless steel electrodes. The conductivity cell is introduced into an airtight cell holder that allows electrical contact. Conductivity measurements are performed in an Instron (Burlington, Ontario, Canada) thermostat connected to a computer-driven controller. Mode 4192A Hewlett-Packar
Frequency range 5 using d impedance analyzer
Impedance data was collected at 10 ° C. intervals between Hz and 13 MHz.

PEO-LiTFSI- (NES-I-
6) The conductivity of the mixture is about twice that of PEO-LiTFSI-TES and is one order of magnitude higher (0 ° C.) than PEO-LiTFSI system.

Example 4 In this example, LiTFSI was used at the same concentration (0.37 M).
Compare the electrochemical stability of NES-II-17 and TES dissolved in the above. A conventional three-electrode cell was used for this test, and the working electrode was a glass carbon rod embedded in Kel-F. The current response as a function of voltage scan (scan speed = 20 mV / sec) was recorded and the results are shown in FIG. NES-II
At −7, substantial solvent oxidation occurs about 7 times more than TES.
It is around 5 V, which is higher by 00 mV. Therefore, NES-II-
7 is a good candidate for a high voltage energy lithium battery.

Example 5 This example compares the effect of various sulfamides on the power and cyclability of a lithium polymer battery. Lithium anode supported on a thin sheet of nickel (thickness 3
Three cells are made from a composite cathode having a volume composition of 5 mm) and about 40% TiS ₂ , 10% acetylene black and 50% ethylene oxide copolymer. The copolymers are described in EPO 0,013,199, U.S. Pat. No. 4,578,326 and U.S. Pat. No. 4,758,48.
About 80% of ethylene oxide as described in No. 3
Containing a lithium salt LiTFSI at a ratio of 30/1
Add. A cathode with an effective capacity of about 3 C / cm ² is mounted on a thin nickel collector. The polymer electrolyte separator is 15 mm thick and is composed of an ethylene oxide based polymer. By hot pressing at 80 ° C,
Assemble the battery with an effective surface of 3.89 cm ² . Sulfamide is added to the separator and cathode just before the hot pressure step, so that the ratio of molecular sulfamide introduced to the amount of LiTFSI in the cell is 1: 1.

At a constant current (charge and discharge) at 25 ° C., a speed of about C
The battery is cycled at / 40 and the discharge power performance of these cells is obtained between 7 and 15 cycles. As is clear from FIG. 4, the cells to which NES-I-3 and NES-II-65 are added maintain a higher capacity than TES at the rate C / x (x = 20 to 4). The cyclability of C / 40 in all cells is very good and comparable.

[Brief description of the drawings]

FIG. 1 is a graph showing the increase in conductivity of NES-I-4 compared to TES.

FIG. 2: PEO-LiTFSI mixture containing 35% by weight of LiTFSI, PEO-LiTFSI-
NES-I-6 (9% by weight) mixture and PEO-LiT
2 shows the conductivity of an FSI-TES (8% by weight) mixture.

FIG. 3 is a graph comparing the electrochemical stability of NES-II-7 and TES.

FIG. 4 is a graph comparing the cycling capacities of cells with NES-I-3 and NES-II-65 and cells with TES.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification code FI H01M 6/18 H01M 10/40 A 10/40 B H01G 9/00 301D (72) Inventor Dennis Gravel J4S1 in Canada 1 El 3 Quebec, Saint-Lambert, des Pyrenees 207 (72) Inventor, Michelle Alman, Ash 3te, Canada 1N2 Quebec, Montreal, Liu Fundar 2965 (72) Inventor, Nazredine Slogi Ash, 2 Canada 1 Zed 7 Quebec, Montreal, Papineau 9780, Appartement 34 (72) Inventor Eve Choquett Canadian Gi3 1 1 4 Quebec, Saint-Julier, Liu Albert-Roséau 940 (72) Inventor Gerard Pelon Canada 4b 6j1 Quebec, Boucherville, de Merle 340 (72) Inventor Danny Bruwit Ash, 3 Canada 1 ale 7 Quebec, Montreal, Ride 2655 (72) Inventor Jezier Blizzard, Canada 1 Ash 2S2 Quebec, Sherbrooke, Saint-André 1430 (72) Inventor Michel Palan J0M 1 Canadian Canadian Jémé 0, Bose, Linier, Utième Avenue 1341, Koli Postal 333 (72) Inventor Jerk Prudhem Ashve, Canada 3p1 Kebek, Laval, Saint-Canto-Nevième-Avenue 204 (72) Inventor Christian Labrès Canada 0, 3 Ash0, Quebec, Saint-Roche de Dou Lakigan, Luisau de Ange Sud 503

Claims (27)

[Claims] 1. A compound of the general formula: R ₁ R ₂ NSO ₂ NR ₃ R _{4 wherein} 1 to 3 R substituents are methyl groups and the rest are ethyl groups, or one R is A methoxyethyl group and the remaining R is a methyl or ethyl group) or a sulfamide or mixture for an aprotic solvent. 2. The sulfamide of claim 1, wherein R ₁ = R ₂ = R ₃ = methyl, R ₄ = ethyl, and has a dielectric constant of 57 and a melting point of −33 ° C. 3. R ₁ = R ₂ = methyl, R ₃ = R ₄ = ethyl, a dielectric constant of 40.5 and a melting point of −24 ° C.
Sulfamide according to claim 1, having a glass transition temperature of 122 ° C. 4. R ₁ = R ₃ = methyl, R ₂ = R ₄ = ethyl, dielectric constant of 44, melting point of −56 ° C. and −13.
2. A glass transition temperature of 0 ° C.
The sulfamide according to the above. 5. R ₁ = R ₂ = R ₃ = methyl, R ₄ = methoxyethyl, a dielectric constant of 41.7 and -110 ° C.
The sulfamide according to claim 1, having a glass transition temperature of: 6. R ₁ = R ₂ = R ₃ = ethyl, R ₄ = methoxyethyl, a dielectric constant of 29, a glass transition temperature of −118 ° C., and 0 to 5 V vs. The sulfamide of claim 1 having a lithium stability window. 7. An electrolyte composition comprising at least one sulfamide composition according to claim 1 and at least one dissociable salt dissolved in the composition. 8. The electrolyte composition according to claim 7, wherein the sulfamide is a mixture with an auxiliary solvent. 9. The electrolyte composition according to claim 7, wherein the salt is a lithium salt. 10. The method according to claim 10, wherein the lithium salt is LiBF ₄ , LiPF ₆ ,
Li (R _F SO ₂ ) ₂ N, Li (R _F SO ₂ ) ₃ C (where R
The electrolyte composition according to claim 8, wherein _F is selected from the group consisting of fluorine and a fluorocarbon group having 1 to 4 carbon atoms. 11. The method according to claim 8, wherein the auxiliary solvent is selected from the group consisting of dimethyl ethers of ethylene glycol, diethylene glycol and triethylene glycol and / or ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and γ-butyrolactone. The electrolyte composition according to any of the preceding claims. 12. The electrolyte composition according to claim 7, wherein the sulfamide is a mixture with an aprotic polymer. 13. An aprotic polymer having at least 7
13. The electrolyte of claim 12, wherein the electrolyte is selected from the group consisting of polyethers containing 0% ethylene oxide units, poly (methyl methacrylate), poly (acrylonitrile), and copolymers containing at least 70% vinylidene fluoride units. Composition. 14. The ratio of sulfamide to polymer is 20%
14. The electrolyte composition according to claim 11, wherein sulfamide acts as a plasticizer. 15. The method according to claim 11, wherein the ratio of the solvent to the polymer is 50% or more, and the resulting mixture forms a gel.
4. The electrolyte composition according to 3. 16. The electrolyte composition according to claim 11, wherein the solvent to polymer ratio is less than 50% and the resulting mixture is a highly plasticized polymer-based system. 17. A lithium battery, wherein the electrolyte comprises the electrolyte composition according to claim 7 as a single component or as a component of a composite electrode. 18. The negative electrode may be lithium metal, a lithium alloy,
18. The lithium battery according to claim 17, comprising a carbon insertion compound or a low voltage insertion oxide or nitride. 19. The positive electrode comprises a high voltage insertion electrode derived from vanadium oxide, manganese oxide, cobalt oxide, nickel oxide, iron phosphate, iron pyrophosphate, iron manganese phosphate or iron manganese pyrophosphate. 19. The lithium battery according to 18. 20. The cathode of claim 17, comprising polydisulfide or sulfur mixed with a conductive additive such as high surface area carbon.
Or a lithium battery according to 18. 21. A supercapacitive device wherein the electrolyte comprises the composition according to any one of claims 7 to 16. 22. An electrode comprising high surface area carbon.
2. The supercapacitive device according to 1. 23. An electrochemical device wherein the electrolyte comprises the composition according to any one of claims 7 to 16. 24. The electrochemical device according to claim 23, wherein the electrode is a thin film of tungsten trioxide. 25. A solvent composition for a medium, comprising the sulfamide according to claim 1 alone or as a mixture with an organic solvent. 26. The solvent composition according to claim 25, wherein the auxiliary solvent is an aromatic hydrocarbon or a halocarbon. 27. Carbanion production, Friedel-Crafts reaction, Diels-Alder or Michaelis reaction,
The solvent composition according to claim 25 or 26, which is used as a medium for an organic reaction containing cationic or anionic polymerization.